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Abstract:

A dry-in/dry-out system is disclosed for wafer electroless plating. The
system includes an upper zone for wafer ingress/egress and drying
operations. Proximity heads are provided in the upper zone to perform the
drying operations. The system also includes a lower zone for electroless
plating operations. The lower zone includes an electroless plating
apparatus that implements a wafer submersion by fluid upwelling method.
The upper and lower zones of the system are enclosed by a dual-walled
chamber, wherein the inner wall is a chemically inert plastic and the
outer wall is a structural metal. The system interfaces with a fluid
handling system which provides the necessary chemistry supply and control
for the system. The system is ambient controlled. Also, the system
interfaces with an ambient controlled managed transfer module (MTM).

Claims:

1. A semiconductor wafer electroless plating system, comprising: a chamber
equipped to,receive a wafer in a dry state from an interfacing
module,perform an electroless plating process on the wafer within the
chamber,perform a drying process on the wafer within the chamber,
andprovide the wafer in a dry state to the interfacing module,wherein the
chamber is defined to perform the electroless plating process and the
drying process within a common internal volume of the chamber.

2. A semiconductor wafer electroless plating system as recited in claim 1,
wherein the chamber includes an inner liner and outer structural walls,
the inner liner configured to be inserted within a volume defined by the
outer structural walls and in a partially spaced apart relationship with
the outer structural walls.

3. A semiconductor wafer electroless plating system as recited in claim 2,
wherein the inner liner is formed from a chemically inert material and
the outer structural walls are formed of a structural material capable of
maintaining a vacuum boundary.

4. A semiconductor wafer electroless plating system as recited in claim 1,
wherein the chamber is defined to control an ambient condition within the
common internal volume of the chamber.

5. A semiconductor wafer electroless plating system as recited in claim 1,
wherein the chamber includes a drive roller assembly and a stabilizer
assembly defined to work together to support the wafer in a substantially
horizontal orientation in an upper region of the chamber upon receipt of
the wafer from the interfacing module, during the drying process, and for
provision of the wafer to the interfacing module.

6. A semiconductor wafer electroless plating system as recited in claim 5,
wherein the drive roller assembly and the stabilizer assembly are defined
to rotate the wafer while maintaining the wafer in the substantially
horizontal orientation in the upper region of the chamber.

7. A semiconductor wafer electroless plating system as recited in claim 1,
wherein the chamber includes a fluid bowl disposed in a lower region of
the chamber, the fluid bowl defined to receive the wafer in a
substantially horizontal orientation within an interior volume of the
fluid bowl and contain an electroless plating solution when the
electroless plating solution is flowed into the fluid bowl so as to cover
a top surface of the wafer.

8. A semiconductor wafer electroless plating system as recited in claim 1,
wherein the chamber includes a platen defined to support the wafer during
the electroless plating process, the chamber further including a platen
lift assembly for moving the platen from an upper region of the chamber
where the wafer is to be received from and provided to the interfacing
module and subjected to the drying process, to a lower region of the
chamber where the wafer is to be subjected to the electroless plating
process.

9. A semiconductor wafer electroless plating system as recited in claim 1,
wherein the chamber includes an upper proximity head and a lower
proximity head that are each defined to traverse the wafer when present
in an upper region of the chamber, the upper and lower proximity heads
defined to perform the drying process on the wafer.

10. A semiconductor wafer electroless plating system as recited in claim
1, further comprising:a fluid handling system equipped to support the
electroless plating process and the drying process within the common
internal volume of the chamber.

11. A chamber for semiconductor wafer electroless plating, comprising:a
first wafer processing zone defined within an upper region of an internal
volume of the chamber, the first wafer processing zone equipped to
perform a drying process on a wafer when disposed within the first wafer
processing zone;a second wafer processing zone defined within a lower
region of the internal volume of the chamber, the second wafer processing
zone equipped to perform an electroless plating process on the wafer when
disposed within the second wafer processing zone; anda platen defined to
support the wafer within the second wafer processing zone and provide
transport of the wafer between each of the first and second wafer
processing zones.

12. A chamber for semiconductor wafer electroless plating as recited in
claim 11, wherein the first wafer processing zone includes a drive roller
assembly and a stabilizer roller assembly defined to engage and support
the wafer in a substantially horizontal orientation and provide wafer
rotational capability.

13. A chamber for semiconductor wafer electroless plating as recited in
claim 12, wherein the first wafer processing zone includes an upper
proximity head and a lower proximity head that are each defined to
traverse the wafer when engaged by the drive roller assembly and the
stabilizer roller assembly, the upper and lower proximity heads defined
to perform the drying process on the wafer through application of a
respective dynamic liquid meniscus to the wafer.

14. A chamber for semiconductor wafer electroless plating as recited in
claim 11, wherein the first wafer processing zone includes a chamber
entry door through which the wafer is to be received into the chamber and
provided from the chamber.

15. A chamber for semiconductor wafer electroless plating as recited in
claim 11, wherein the second wafer processing zone includes a fluid bowl
defined to receive the platen in a substantially horizontal orientation
within an interior volume of the fluid bowl and contain an electroless
plating solution when the electroless plating solution is flowed into the
fluid bowl so as to cover the platen an a top surface of the wafer when
present on the platen.

16. A chamber for semiconductor wafer electroless plating as recited in
claim 11, wherein the second wafer processing zone includes one or more
rinse nozzles defined to direct a rinsing fluid toward a top surface of
the platen so as to remove electroless plating solution from the top
surface of the wafer when present on the platen.

17. A chamber for semiconductor wafer electroless plating as recited in
claim 11, wherein the platen is defined to be heated in a controlled
manner so as to enable control of a temperature of the wafer when present
on the platen.

18. A chamber for semiconductor wafer electroless plating as recited in
claim 11, wherein the platen includes a number of vacuum channels fluidly
connected to a vacuum supply to enable a vacuum chucking of the wafer to
the platen when the wafer is present on the platen.

19. A chamber for semiconductor wafer electroless plating as recited in
claim 11, wherein the chamber is defined by outer structural walls and an
inner liner, the inner liner configured to be inserted within the outer
structural walls so as to form the internal volume of the chamber,
wherein the outer structural walls are formed of a structural material
capable of maintaining a vacuum boundary, and the inner liner is formed
from a chemically inert material.

20. A method for operating a semiconductor wafer electroless plating
system, comprising:receiving a wafer in a dry state within a chamber
volume;performing an electroless plating process on the wafer within the
chamber volume;performing a rinsing process on the wafer within the
chamber volume;performing a drying process on the wafer within the
chamber volume; andproviding the wafer in a dry state from the chamber
volume.

21. A method for operating a semiconductor wafer electroless plating
system as recited in claim 20, wherein the wafer is received within an
upper region of the chamber volume, the electroless plating and rinsing
processes are performed in a lower region of the chamber volume, and the
drying process is performed within the upper region of the chamber.

22. A method for operating a semiconductor wafer electroless plating
system as recited in claim 21, wherein performing the electroless plating
process on the wafer within the chamber volume includes,supporting the
wafer in a fluid bowl,filling the fluid bowl with electroless plating
solution so that the electroless plating solution rises up and over a
periphery of the wafer so as to cover a top surface of the wafer,
anddraining the electroless plating solution from the top surface of the
wafer following an electroless plating reaction period.

23. A method for operating a semiconductor wafer electroless plating
system as recited in claim 20, wherein the rinsing process is performed
on the wafer promptly after completion of the electroless plating process
by dispensing a rinsing fluid onto a top surface of the wafer.

24. A method for operating a semiconductor wafer electroless plating
system as recited in claim 20, wherein the drying process is performed on
a top surface of the wafer by scanning an upper proximity head over the
top surface of the wafer so as to subject the top surface of the wafer to
a first dynamic liquid meniscus, and wherein the drying process is
performed on a bottom surface of the wafer by scanning a lower proximity
head over the bottom surface of the wafer so as to subject the bottom
surface of the wafer to a second dynamic liquid meniscus.

25. A method for operating a semiconductor wafer electroless plating
system as recited in claim 20, further comprising:controlling an ambient
condition within the chamber volume so as to minimize an oxygen content
within the chamber volume.

26. A method for operating a semiconductor wafer electroless plating
system as recited in claim 20, further comprising:controlling a vapor
pressure within the chamber to be at a saturated state relative to an
electroless plating solution to be applied over the wafer.

[0002]In the fabrication of semiconductor devices such as integrated
circuits, memory cells, and the like, a series of manufacturing
operations are performed to define features on semiconductor wafers
("wafers"). The wafers include integrated circuit devices in the form of
multi-level structures defined on a silicon substrate. At a substrate
level, transistor devices with diffusion regions are formed. In
subsequent levels, interconnect metallization lines are patterned and
electrically connected to the transistor devices to define a desired
integrated circuit device. Also, patterned conductive layers are
insulated from other conductive layers by dielectric materials.

[0003]To build an integrated circuit, transistors are first created on the
surface of the wafer. The wiring and insulating structures are then added
as multiple thin-film layers through a series of manufacturing process
steps. Typically, a first layer of dielectric (insulating) material is
deposited on top of the formed transistors. Subsequent layers of metal
(e.g., copper, aluminum, etc.) are formed on top of this base layer,
etched to create the conductive lines that carry the electricity, and
then filled with dielectric material to create the necessary insulators
between the lines.

[0004]Although copper lines are typically comprised of a PVD seed layer
(PVD Cu) followed by an electroplated layer (ECP Cu), electroless
chemistries are under consideration for use as a PVD Cu replacement, and
even as a ECP Cu replacement. Electroless copper (Cu) and electroless
cobalt (Co) are potential techniques for improving interconnect
reliability and performance. Electroless Cu can be used to form a thin
conformal seed layer on a conformal barrier to optimize a gapfill process
and minimize void formation. Further, deposition of a selective Co
capping layer on planarized Cu lines can improve adhesion of the
dielectric barrier layer to the Cu lines, and suppress void formation and
propagation at the Cu-dielectric barrier interface.

[0005]During the electroless plating process, electrons are transferred
from a reducing agent to the Cu (or Co) ions in the solution resulting in
the deposition of reduced Cu (or Co) onto the wafer surface. The
formulation of the electroless copper plating solution is optimized to
maximize the electron transfer process involving the Cu (or Co) ions in
solution. The plating thickness achieved through the electroless plating
process is dependent on the residency time of the electroless plating
solution on the wafer. Because the electroless plating reactions occur
immediately and continuously upon exposure of the wafer to the
electroless plating solution, it is desirable to perform the electroless
plating process in a controlled manner and under controlled conditions.
To this end, a need exists for an improved electroless plating apparatus.

SUMMARY OF THE INVENTION

[0006]In one embodiment, a semiconductor wafer electroless plating system
is disclosed. The system includes a chamber equipped to receive a wafer
in a dry state from an interfacing module. The chamber is equipped to
perform an electroless plating process on the wafer within the chamber.
Also, the chamber is equipped to perform a drying process on the wafer
within the chamber. The chamber is defined such that the electroless
plating process and the drying process are performed within a common
internal volume of the chamber. The chamber is further equipped to
provide the wafer in a dry state to the interfacing module.

[0007]In another embodiment, a chamber for semiconductor wafer electroless
plating is disclosed. The chamber includes a first wafer processing zone
defined within an upper region of an internal volume of the chamber. The
first wafer processing zone is equipped to perform a drying process on a
wafer when disposed within the first wafer processing zone. The chamber
also includes a second wafer processing zone defined within a lower
region of the internal volume of the chamber. The second wafer processing
zone is equipped to perform an electroless plating process on the wafer
when disposed within the second wafer processing zone. The chamber
further includes a platen defined to support the wafer within the second
wafer processing zone and transport the wafer between each of the first
and second wafer processing zones.

[0008]In another embodiment, a method is disclosed for operating a
semiconductor wafer electroless plating system. The method includes an
operation for receiving a wafer in a dry state within a chamber volume.
The method also includes performing an electroless plating process on the
wafer within the chamber volume. Then, a rinsing process is performed on
the wafer within the chamber volume. Also, following the rinsing process,
a drying process is performed on the wafer within the chamber volume. The
method further includes an operation for providing the wafer in a dry
state from the chamber volume.

[0009]Other aspects and advantages of the invention will become more
apparent from the following detailed description, taken in conjunction
with the accompanying drawings, illustrating by way of example the
present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is an illustration showing an isometric view of a
dry-in/dry-out electroless plating chamber, in accordance with one
embodiment of the present invention;

[0011]FIG. 2 is an illustration showing a vertical cross-section through a
center of the chamber, in accordance with one embodiment of the present
invention;

[0012]FIG. 3 is an illustration showing a top view of the chamber with the
upper prox head extended to the center of the wafer, in accordance with
one embodiment of the present invention;

[0013]FIG. 4 is an illustration showing a top view of the chamber with the
upper prox head retracted to the home position over the prox head docking
station, in accordance with one embodiment of the present invention;

[0014]FIG. 5 is an illustration showing an isometric view of the entry
door, in accordance with one embodiment of the present invention;

[0015]FIG. 6 is an illustration showing an isometric view of the
stabilizer assembly, in accordance with one embodiment of the present
invention;

[0016]FIG. 7 is an illustration showing the drive roller assembly, in
accordance with one embodiment of the present invention;

[0017]FIG. 8 is an illustration showing an isometric view of the platen
lift assembly, in accordance with one embodiment of the present
invention;

[0018]FIG. 9 is an illustration showing a vertical cross-section through
the platen and fluid bowl with the platen in a fully lowered position, in
accordance with one embodiment of the present invention;

[0019]FIG. 10 is an illustration showing an exemplary process that may be
conducted by a prox head, in accordance with one embodiment of the
present invention; and

[0020]FIG. 11 is an illustration showing a cluster architecture, in
accordance with one embodiment of the present invention.

DETAILED DESCRIPTION

[0021]In the following description, numerous specific details are set
forth in order to provide a thorough understanding of the present
invention. It will be apparent, however, to one skilled in the art that
the present invention may be practiced without some or all of these
specific details. In other instances, well known process operations have
not been described in detail in order not to unnecessarily obscure the
present invention.

[0022]FIG. 1 is an illustration showing an isometric view of a
dry-in/dry-out electroless plating chamber 100 ("chamber 100" hereafter),
in accordance with one embodiment of the present invention. The chamber
100 is defined to receive a wafer in a dry state, perform an electroless
plating process on the wafer, perform a rinsing process on the wafer,
perform a drying process on the wafer, and provide the processed wafer in
a dry state. The chamber 100 is capable of performing essentially any
type of electroless plating process. For example, the chamber 100 is
capable of performing an electroless Cu or Co plating process on the
wafer. Additionally, the chamber 100 is configured to be integrated
within a modular wafer processing system. For example, in one embodiment,
the chamber 100 is connected with a managed atmospheric transfer module
(MTM). For additional information regarding the MTM, reference can be
made to U.S. patent application Ser. No. 11/639,752, filed on Dec. 15,
2006, and entitled "Controlled Ambient System for Interface Engineering,"
which is incorporated herein by reference.

[0024]The chamber 100 is equipped to receive a wafer in a dry state from
an interfacing module, such as the MTM. The chamber 100 is equipped to
perform an electroless plating process on the wafer within the chamber
100. The chamber 100 is defined to perform a drying process on the wafer
within the chamber 100. The chamber 100 is defined to provide the wafer
in a dry state back to the interfacing module. It should be appreciated
that the chamber 100 is defined to perform the electroless plating
process and the drying process on the wafer within a common internal
volume of the chamber 100. Additionally, a fluid handling system (FHS) is
provided to support the wafer electroless plating process and the wafer
drying process within the common internal volume of the chamber 100.

[0025]The chamber 100 includes a first wafer processing zone defined
within an upper region of an internal volume of the chamber 100. The
first wafer processing zone is equipped to perform the drying process on
the wafer when disposed within the first wafer processing zone. The
chamber 100 also includes a second wafer processing zone defined within a
lower region of the internal volume of the chamber 100. The second wafer
processing zone is equipped to perform the electroless plating process on
the wafer when disposed within the second wafer processing zone.
Additionally, the chamber 100 includes a platen that is vertically
movable between the first and second wafer processing zones within the
internal volume of the chamber 100. The platen is defined to transport
the wafer between the first and second processing zones and support the
wafer within the second processing zone during the electroless plating
process.

[0026]With regard to FIG. 1, the chamber 100 is defined by outer structure
walls 103 including an outer structural bottom and a structural top 105.
The outer structure of the chamber 100 is capable of resisting forces
associated with a sub-atmospheric pressure, i.e., vacuum, condition
within the internal volume of the chamber 100. The outer structure of the
chamber 100 is also capable of resisting forces associated with an
above-atmospheric pressure condition within the internal volume of the
chamber 100. In one embodiment, the structural top 105 of the chamber is
equipped with a window 107A. Additionally, in one embodiment a window
107B is provided in an outer structural wall 103 of the chamber. It
should be understood, however, that the windows 107A and 107B are not
critical to the operation of the chamber 100. For example, in one
embodiment, the chamber 100 is defined without windows 107A and 107B.

[0027]The chamber 100 is defined to sit atop a frame assembly 109. It
should be understood that other embodiments may utilize a frame assembly
that is different from the exemplary frame assembly 109 depicted in FIG.
1. The chamber 100 is defined to include an entry door 101 through which
a wafer is inserted into and removed from the chamber 100. The chamber
100 further includes a stabilizer assembly 305, a platen lift assembly
115, and a proximity head drive mechanism 113, each of which will be
described in more detail below.

[0028]FIG. 2 is an illustration showing a vertical cross-section through a
center of the chamber 100, in accordance with one embodiment of the
present invention. The chamber 100 is defined such that when a wafer 207
is inserted through the entry door 101, the wafer 207 will be engaged by
a drive roller assembly 303 (not shown) and the stabilizer assembly 305
within the upper region of the chamber internal volume. By way of the
platen lift assembly 115, a platen 209 is defined to travel in a vertical
direction between the upper and lower regions of the chamber internal
volume. The platen 209 is defined to receive the wafer 207 from the drive
roller assembly 303 and stabilizer assembly 305, and move the wafer 207
to the second wafer processing zone in the lower region of the chamber
internal volume. As will be described in more detail below, within the
lower region of the chamber, the platen 209 is defined to interface with
a fluid bowl 211 to enable the electroless plating process.

[0029]Following the electroless plating process within the lower region of
the chamber, the wafer 207 is lifted via the platen 209 and platen lift
assembly 115 back to the position where it can be engaged by the drive
roller assembly 303 and the stabilizer assembly 305. Once securely
engaged by the drive roller assembly 303 and the stabilizer assembly 305,
the platen 209 is lowered to a position within the lower region of the
chamber 100. The wafer 207, having been subjected to the electroless
plating process, is then dried by way of an upper proximity ("prox"
hereafter) head 203 and a lower prox head 205. The upper prox head 203 is
defined to dry an upper surface of the wafer 207. The lower prox head is
defined to dry a lower surface of the wafer 207.

[0030]By way of the prox head drive mechanism 113, the upper and lower
prox heads 203/205 are defined to move in a linear manner across the
wafer 207 when the wafer 207 is engaged by the drive roller assembly 303
and the stabilizer assembly 305. In one embodiment, the upper and lower
prox heads 203/205 are defined to move to a center of the wafer 207 as
the wafer 207 is rotated by the drive roller assembly 303. In this
manner, the wafer 207 upper and lower surfaces can be completely exposed
to the upper and lower prox heads 203/205, respectively. The chamber 100
further includes a prox head docking station 201 for receiving each of
the upper and lower prox heads 203/205 when retracted to their home
position. The prox head docking station 201 also provides for a smooth
transition of the meniscus associated with each of the upper and lower
prox heads 203/205 as the meniscus transitions onto the wafer 207. The
prox head docking station 201 is positioned within the chamber so as to
ensure that when the upper and lower prox heads 203/205 are retracted to
their respective home positions, the upper and lower prox heads 203/205
do not interfere with the drive roller assembly 303, the stabilizer
assembly 305, or the platen 209 when raised to receive the wafer 207.

[0031]FIG. 3 is an illustration showing a top view of the chamber with the
upper prox head 203 extended to the center of the wafer 207, in
accordance with one embodiment of the present invention. FIG. 4 is an
illustration showing a top view of the chamber with the upper prox head
203 retracted to the home position over the prox head docking station
201, in accordance with one embodiment of the present invention. As
previously mentioned, when the wafer 207 is received within the chamber
100 through the entry door 101, the wafer is engaged and held by the
drive roller assembly 303 and the stabilizer assembly 305. By way of the
prox head drive mechanism 113, the upper prox head 203 can be moved in a
linear manner from its home position on the prox head docking station 201
to the center of the wafer 207. Similarly, by way of the prox head drive
mechanism 113, the lower prox head 205 can be moved in a linear manner
from its home position on the prox head docking station 201 to the center
of the wafer 207. In one embodiment, the prox head drive mechanism 113 is
defined to move the upper and lower prox heads 203/205 together from the
prox head docking station 201 to the center of the wafer 207.

[0032]As shown in FIG. 3, the chamber 100 is defined by the outer
structural walls 103 and an inner liner 301. Thus, the chamber 100
incorporates a double-wall system. The outer structural walls 103 have
sufficient strength to provide a vacuum capability within the chamber 100
and thereby form a vacuum boundary. In one embodiment, the outer
structural walls 103 are formed of a structural metal such as stainless
steel. It should be understood, however, that essentially any other
structural material having appropriate strength characteristics can be
used to form the outer structural walls 103. The outer structural walls
103 are also defined with sufficient precision to enable interfacing of
the chamber 100 with another module, such as the MTM.

[0033]The inner liner 301 provides a chemical boundary and acts as a
separator to keep chemicals within the chamber from reaching the outer
structural walls 103. The inner liner 301 is formed of an inert material
that is chemically compatible with the various chemicals that may be
present within the chamber 100. In one embodiment, the inner liner 301 is
formed of an inert plastic material. It should be understood, however,
that essentially any other chemically inert material that can be
appropriately shaped can be used to form the inner liner 301. It should
also be understood that the inner liner 301 is not required to provide a
vacuum boundary. As previously mentioned, the outer structural walls 103
are defined to provide the vacuum boundary. Additionally, in one
embodiment, the inner liner 301 can be removed from the chamber 100 to
facilitate cleaning or to simply be replaced with a new inner liner 301.

[0034]The chamber 100 is defined to be ambient controlled to facilitate
the wafer electroless plating process and protect the wafer surface from
undesirable reactions, e.g., oxidation. To this end, the chamber 100 is
equipped with an internal pressure control system and an internal oxygen
content control system. The chamber 100 internal pressure is capable of
being reduced by way of a vacuum source plumbed to the internal volume of
the chamber 100. The chamber 100 internal pressure is controlled through
use of a pressure controller, such as a Universal Pressure Controller
(UPC). The UPC is defined to read the chamber 100 internal pressure as
measured by a pressure sensor, and maintain the chamber 100 internal
pressure at a setpoint by allowing more of an inert gas, such as
nitrogen, into the chamber 100 internal volume. It should be understood
that the UPC does not actually reduce the pressure within the chamber 100
internal volume, as the vacuum system is provided for pressure reduction
purposes. Additionally, it should be understood that the pressure
controller can be something other than the UPC, so long as the pressure
controller functionality is substantially equivalent to that of the UPC.
However, for ease of description, the pressure controller is referred to
as the UPC hereafter.

[0035]The chamber 100 is also equipped with a slow-pump valve, i.e., a
bleed-through valve, to allow a small amount of the chamber 100 internal
atmosphere to be removed. The amount of chamber 100 internal atmosphere
removed by way of the slow-pump valve is replaced by the UPC so that the
chamber 100 internal pressure remains at setpoint. In one embodiment, the
chamber 100 is capable of being pumped down to less than 100 mTorr. In
one embodiment, it is anticipated that the chamber 100 will be operated
at approximately 700 Torr. Additionally, the chamber 100 is equipped with
a pressure switch plumbed to the internal volume of the chamber 100. The
pressure switch indicates when the pressure within the chamber 100 is at
a pressure level below atmospheric pressure (760 Torr) but above 500
Torr. In one embodiment, the pressure switch can be set to open when the
chamber 100 internal pressure is below 500 Torr.

[0036]The chamber 100 is further defined to enable control of an oxygen
content within the chamber 100 internal volume. It should be appreciated
that the oxygen concentration within the chamber 100 internal volume is
an important process parameter. More specifically, a low oxygen
concentration is required in the wafer processing environment to ensure
that undesirable oxidation reactions are avoided at the wafer surface. It
is anticipated that the oxygen concentration within the chamber 100
internal volume will be maintained at a level less than 2 ppm (parts per
million) when the wafer is present within the chamber 100.

[0037]The oxygen concentration within the chamber 100 is reduced by
evacuating the chamber, by way of a vacuum source plumbed to the internal
volume of the chamber 100, and refilling the chamber 100 internal volume
with high purity nitrogen. Therefore, the oxygen concentration within the
chamber 100 internal volume is reduced from atmospheric levels, i.e.,
about 20% oxygen, by pumping the chamber 100 internal volume down to a
low pressure and refilling the chamber 100 internal volume with ultra
pure nitrogen which has a negligible oxygen content. In one embodiment,
pumping the chamber 100 internal volume down to 1 Torr and refilling it
to atmospheric pressure with ultra pure nitrogen three times should bring
the oxygen concentration within the chamber 100 internal volume down to
about 3 ppm.

[0038]To assist with maintaining the oxygen concentration at an
appropriate level within the chamber 100 internal volume, an oxygen
sensor is mounted to a port on the chamber 100. In one embodiment, the
oxygen sensor is a zirconium oxide based sensor that is defined to output
an electric current that is indicative of the oxygen concentration within
a gas to which the sensor is exposed. The oxygen sensor is calibrated for
a given pressure and a given flow rate of gas traveling past the sensor.
In one embodiment, the oxygen sensor is calibrated to have an accuracy
extending from about ±0.1 ppm to about ±5 ppm of oxygen.

[0039]The electroless plating process is a temperature sensitive process.
Therefore, it is desirable to minimize the influence of the chamber 100
internal volume ambient conditions on the temperature of the electroless
plating solution when present on the wafer surface. To this end, the
chamber 100 is defined such that gases can be introduced into the chamber
100 internal volume through air gaps present between the outer structural
walls 103 and the inner liner 301, so as to avoid flowing of gases
directly over the wafer. It should be appreciated that a flow of gas
directly over the wafer when electroless plating solution is present on
the wafer surface could cause an evaporative cooling effect that would
reduce the temperature of the electroless plating solution present on the
wafer, and correspondingly modify the electroless plating reaction rate.
In addition to the capability of indirectly introducing gas into the
chamber 100 internal volume, the chamber 100 is also equipped to allow a
vapor pressure within the chamber 100 internal volume to be raised to a
saturated state when the electroless plating solution is applied over the
wafer surface. With the chamber 100 internal volume in a saturated state
relative to the electroless plating solution, the above-mentioned
evaporative cooling effect would be minimized.

[0040]FIG. 5 is an illustration showing an isometric view of the entry
door 101, in accordance with one embodiment of the present invention. The
entry door 101 is a shutter type door that shields a chamber entry rocker
valve and outer module, e.g., MTM, from the chamber 100. The entry door
101 assembly includes a shutter 501 which is movable in a vertical
direction to cover the chamber entry rocker valve. An actuator 505 and
linkage 503 are provided with the entry door 101 assembly to enable the
vertical movement of the shutter 501. In one embodiment, the actuator 505
is defined as a pneumatic cylinder. Although the entry door 101 is
exemplified herein as a shutter type door, it should be appreciated that
in other embodiments the chamber 100 can be defined to incorporate other
types of entry doors, so long as the entry door 101 achieves its
objective of shielding the entry rocker valve and outer module from the
chamber 100 internal region.

[0041]FIG. 6 is an illustration showing an isometric view of the
stabilizer assembly 305, in accordance with one embodiment of the present
invention. The stabilizer assembly 305 includes a stabilizer roller 605
that is defined to apply pressure to the edge of the wafer 207 so as to
hold the wafer 207 in the drive roller assembly 303. Thus, the stabilizer
roller 605 is defined to engage the edge of the wafer 207. The stabilizer
roller 605 profile is defined to accommodate an amount of angular
misalignment between the stabilizer roller 605 and the wafer 207. Also,
the stabilizer assembly 305 is defined to enable mechanical adjustment of
the stabilizer roller 605 vertical position. The stabilizer assembly 305
shown in FIG. 6 includes a single stabilizer roller 605 to accommodate a
200 mm wafer. In another embodiment, the stabilizer assembly 305 can be
defined with two stabilizer rollers 605 to accommodate a 300 mm wafer.

[0042]The stabilizer roller 605 is defined on a stabilizer bar 603 to
enable movement of the stabilizer roller 605 toward and away from the
edge of the wafer 207. An actuator 607, such as a pneumatic cylinder, is
provided along with appropriate linkage 609 to enable movement of the
stabilizer bar 603, so as to engage the stabilizer roller 605 with the
wafer 207 edge and disengage the stabilizer roller 605 from the wafer 207
edge. The stabilizer assembly 305 further includes a housing 601 defined
to enable connection of the stabilizer assembly to the chamber 100, and
provide a support frame for the stabilizer bar 603. In one embodiment,
sensors are deployed within the chamber 100 to enable identification of
the position of the stabilizer roller 605 with respect to the wafer 207
edge. For example, in one embodiment, Hall Effect type sensors are
deployed to enable identification of the stabilizer roller 605 as being
either disengaged from the wafer 207, engaged with the wafer 207, or
overshooting the wafer 207 engagement position (such as when the wafer
207 is not present). Additionally, in one embodiment, a vacuum drying
device is mounted to the stabilizer bar 603 to provide for drying of the
stabilizer roller 605, which may be wet due to contact with the wafer 207
prior to the wafer 207 drying process.

[0043]FIG. 7 is an illustration showing the drive roller assembly 303, in
accordance with one embodiment of the present invention. The drive roller
assembly 303 includes a pair of drive rollers 701 defined to engage the
edge of the wafer 207 and rotate the wafer 207. In one embodiment, the
drive rollers 701 are rotated in a common direction and at a common
rotational speed by drive mechanics 705. Each of the drive rollers 701 is
defined to engage the edge of the wafer 207. The profile of each drive
roller 701 is defined to accommodate an amount of angular misaligurnent
between the drive roller 701 and the wafer 207. Also, the drive roller
assembly 303 is defined to enable mechanical adjustment of the vertical
position of each drive roller 701.

[0044]The drive roller assembly 303 includes an extension mechanism 707 to
enable movement of the drive rollers 701 toward and away from the edge of
the wafer 207. In one embodiment, a pneumatic actuator is used to move
the extension mechanism 707 to enable movement of the drive rollers 701
toward and away from the edge of the wafer 207. When the drive rollers
701 are moved to their limit toward the wafer 207 edge, the drive rollers
207 will come to a position just shy of the wafer 207 edge, when the
wafer 207 is in the robot handoff position within the chamber 100.
Engagement of the stabilizer roller 605 with the edge of the wafer 207
will cause the drive rollers 701 to engage the edge of the wafer 207.

[0045]The drive roller assembly 303 further includes a housing 703 defined
to enable connection of the drive roller assembly 303 to the chamber 100,
and provide a support frame for the drive mechanics 705, extension
mechanism 707, and drive rollers 701. In one embodiment, sensors are
deployed within the chamber 100 to enable identification of the position
of the drive rollers 701 with respect to the wafer 207 edge. For example,
in one embodiment, optical beam break type sensors are deployed to enable
identification of the position of the drive roller assembly 303 with
respect to the wafer 207, i.e., closed (drive roller assembly 303 move to
its limit toward the wafer 207, or open (drive roller assembly 303 fully
retracted away from the wafer 207). Additionally, in one embodiment, a
vacuum drying device is mounted to the drive roller assembly 303 to
provide for drying of the drive rollers 701, which may be wet due to
contact with the wafer 207 prior to the wafer 207 drying process.

[0046]FIG. 8 is an illustration showing an isometric view of the platen
lift assembly 115, in accordance with one embodiment of the present
invention. The platen lift assembly 115 includes a shaft 801 upon which
the platen 209 is mounted. A lower end of the shaft 801 is fixed to a
lift frame 807. The lift frame 807 is defined to move in a vertical
direction so as to move the shaft 801 and platen 209 in a vertical
direction. In one embodiment, the platen lift assembly 115 includes a
linear encoder to provide platen 209 position feedback. Movement of the
platen 209 is controlled through a control module that receives signals
from the linear encoder indicating the position of the platen 209. The
platen lift assembly 115 is defined to move the wafer 207 on the platen
209 from the wafer rotation plane, i.e., the plane where the wafer is
engaged by the drive rollers 701 and stabilizer roller 605, to the
processing position where the platen 209 engages a seal of the fluid bowl
211.

[0047]Lift mechanics 805 are provided to enable the vertical movement of
the lift frame 807, shaft 801, and platen 209. In various embodiments,
the lift mechanics 805 can incorporate electrical motors and/or pneumatic
actuators, and appropriate gearing and linkage to provide vertical
movement to the lift frame 807, shaft 801, and platen 209. In one
embodiment, a DC servo motor is provided to rotate a leadscrew which
drives the lift frame 807 up and down, thus driving the platen 209 up and
down within the chamber via the shaft 801. Also, in one embodiment, a
pneumatic assembly is provided to assist the lift of the platen 209 in
its initial movement against a suction vacuum between the platen 209 and
a seal of the fluid bowl 211. The platen lift assembly 115 also includes
a support frame 803 which provides stable support structure for the lift
frame 807 and lift mechanics 805. The support frame 803 is defined to
interface with a lower surface of the chamber 100, such that the platen
lift assembly 115 will provide for vertical movement of the platen 209
within the chamber 100 internal volume.

[0048]FIG. 9 is an illustration showing a vertical cross-section through
the platen 209 and fluid bowl 211 with the platen 209 in a fully lowered
position, in accordance with one embodiment of the present invention. The
platen 209 is defined as a heated vacuum chuck. In one embodiment, the
platen 209 is fabricated from a chemically inert material. In another
embodiment, the platen 209 is coated with a chemically inert material.
The platen 209 includes vacuum channels 907 connected to a vacuum supply
911, which upon actuation will vacuum clamp the wafer 207 to the platen
209. Vacuum clamping of the wafer 207 to the platen 209 decreases a
thermal resistance between the platen 209 and the wafer 207 and also
prevents the wafer 207 from sliding during vertical transport within the
chamber 100.

[0049]In various embodiments, the platen 209 can be defined to accommodate
a 200 mm wafer or a 300 mm wafer. Additionally, it should be appreciated
that the platen 209 and chamber 100 can be defined to accommodate
essentially any size wafer. For a given wafer size, a diameter of the
platen 209 upper surface, i.e., clamping surface, is defined to be
slightly less than a diameter of the wafer. This platen-to-wafer sizing
arrangement enables the edge of the wafer to extend slightly beyond the
upper peripheral edge of the platen 209, thus enabling engagement between
the wafer edge and each of the stabilizer roller 605 and drive rollers
701 when the wafer is sitting upon the platen 209.

[0050]As previously mentioned, the electroless plating process is a
temperature sensitive process. The platen 209 is defined to be heated so
that the temperature of the wafer 207 can be controlled. In one
embodiment, the platen 209 is capable of maintaining a temperature up to
100° C. Also, the platen 209 is capable of maintaining a
temperature as low as 0° C. It is anticipated that a normal platen
209 operating temperature will be about 60° C. In the embodiment
where the platen 209 is sized to accommodate a 300 mm wafer, the platen
209 is defined with two interior resistive heating coils so as to form an
inner heating zone and an outer heating zone, respectively. Each heating
zone includes its own control thermocouple. In one embodiment, the inner
heating zone utilizes a 700 Watt (W) resistive heating coil, and the
outer zone utilizes a 2000 W resistive heating coil. In the embodiment
where the platen 209 is sized to accommodate a 200 mm wafer, the platen
209 includes a single heating zone defined by a 1250 W interior heating
coil and corresponding control thermocouple.

[0051]The fluid bowl 211 is defined to receive the platen 209 when the
platen 209 is fully lowered within the chamber 100. The fluid holding
capability of the fluid bowl 211 is completed when the platen 209 is
lowered to engage a fluid bowl seal 909 defined about an inner periphery
of the fluid bowl 211. In one embodiment, the fluid bowl seal 909 is an
energized seal which forms a liquid tight seal between the platen 290 and
fluid bowl 211, when the platen 209 is lowered to fully contact the fluid
bowl seal 909. It should be appreciated that when the platen 209 is
lowered to engage the fluid bowl seal 909, a gap exists between the
platen 209 and the fluid bowl 211. Thus, engagement of the platen 209
with the fluid bowl seal 909 allows an electroplating solution to be
injected into the bowl so as to fill the gap that exists between the
platen 209 and the fluid bowl 211 above the fluid bowl seal 909, and
well-up over the periphery of the wafer 207 that is clamped on the upper
surface of the platen 209.

[0052]In one embodiment, the fluid bowl 211 includes eight fluid dispense
nozzles for dispensing of the electroplating solution within the fluid
bowl 211. The fluid dispense nozzles are distributed in a uniformly
spaced manner around the fluid bowl 211. Each of the fluid dispense
nozzles is fed by a tube from a distribution manifold such that a fluid
dispense rate from each fluid dispense nozzle is substantially the same.
Also, the fluid dispense nozzles are disposed such that fluid emanating
from each of the fluid dispense nozzles enters the fluid bowl 211 at a
location below the upper surface of the platen 209, i.e., below the wafer
207 that is clamped on the upper surface of the platen 209. Additionally,
when the platen 209 and wafer 207 are not present in the fluid bowl 211,
the fluid bowl 211 can be cleaned by injecting a cleaning solution into
the fluid bowl 211 through the fluid dispense nozzles. The fluid bowl 211
can be cleaned at a user defined frequency. For example, the fluid bowl
can be cleaned as frequently as after processing of every wafer, or as
infrequently as once every 100 wafers.

[0053]The chamber 100 also includes a rinse bar 901, which includes a
number of rinse nozzles 903 and a number of blowdown nozzles 905. The
rinse nozzles 903 are directed to spray rinse fluid on the top surface of
the wafer 207 when the platen 209 is moved to place the wafer 207 in
rinse position. At the rinse position, a space will exist between the
platen 209 and the fluid bowl seal 909 to enable flow of rinse fluid into
the fluid bowl 211 from which it can be drained. In one embodiment, two
rinse nozzles 903 are provided for rinsing a 300 mm wafer, and one rinse
nozzle 903 is provided for rinsing a 200 mm wafer. The blowdown nozzles
905 are defined to direct an inert gas, such as nitrogen, toward the top
surface of the wafer to assist in removing fluid from the top surface of
the wafer during the rinsing process. It should be appreciated that
because the electroless plating reactions continuously occur when the
electroless plating solution is in contact with the wafer surface, it is
necessary to promptly and uniformly remove the electroless plating
solution from the wafer upon completion of the electroless plating
period. To this end, the rinse nozzles 903 and blowdown nozzles 905
enable prompt and uniform removal of the electroless plating solution
from the wafer 207.

[0054]Operations of the chamber 100 are supported by a fluid handling
system (FHS). In one embodiment, the FHS is defined as a separate module
from the chamber 100 and is connected in fluid communication with various
components within the chamber 100. The FHS is defined to service the
electroless plating process, i.e., the fluid bowl dispense nozzles, rinse
nozzles, and blowdown nozzles. The FHS is also defined to service the
upper and lower prox heads 203/205. A mixing manifold is disposed between
the FHS and the supply line that services each of the fluid dispense
nozzles within the fluid bowl 211. Thus, the electroless plating solution
that flows to each of the fluid dispense nozzles within the fluid bowl
211 is pre-mixed prior to reaching the fluid bowl 211.

[0055]Fluid supply lines are disposed to fluidly connect the mixing
manifold to the various fluid dispense nozzles within the fluid bowl 211,
such that the electroplating solution will flow into the fluid bowl 211
from each fluid dispense nozzle in a substantially uniform manner, e.g.,
at a substantially uniform flow rate. The FHS is defined to enable a
nitrogen purge of the fluid supply lines disposed between the mixing
manifold and the fluid dispense nozzles within the fluid bowl 211, so as
to enable clearing of the fluid supply lines of electroplating solution.
The FHS is also defined to support the wafer rinsing process by providing
rinsing fluid to each of the rinse nozzles 903 and by providing inert gas
to each of the blowdown nozzles 905. The FHS is defined to enable manual
setting of a pressure regulator to control the liquid pressure emanating
from the rinse nozzles 903.

[0056]The chamber 100 includes a number of fluid drain locations. In one
embodiment, three separate fluid drain locations are provided within the
chamber 100: 1) a primary drain from the fluid bowl 211, 2) a chamber
floor drain, and 3) a platen vacuum tank drain. Each of these drains is
connected to a common facility drain provided within the FHS. The fluid
bowl 211 drain is plumbed from the fluid bowl 211 to a chamber drain
tank. A valve is provided to control the draining of fluid from the fluid
bowl 211 to the chamber drain tank. This valve is configured to open when
fluid is present within the drain line extending from the fluid bowl 211
to the chamber drain tank.

[0057]The chamber floor drain is also plumbed to the chamber drain tank.
In the event of a liquid spill within the chamber, liquid will drain from
a port in the chamber floor, i.e., the chamber floor drain, to the
chamber drain tank. A valve is provided to control the draining of fluid
from the chamber floor to the chamber drain tank. This valve is
configured to open when fluid is present within the drain line extending
from the chamber floor to the chamber drain tank.

[0058]The vacuum supply 911 of the platen 209 is provided by a platen
vacuum tank. The platen vacuum tank is equipped with its own drain tank,
i.e., the platen drain tank. The platen drain tank also serves as a
vacuum tank. A vacuum generator is connected to the platen drain tank and
is the source of the backside wafer vacuum provided by way of the vacuum
supply 911. Valves are provided to control the vacuum within the vacuum
channels 907 of the platen 209, i.e., the vacuum present at the backside
of the wafer 207. Sensors are also provided to monitor the vacuum
pressure present at the backside of the wafer 207. In one embodiment, the
platen drain tank and chamber drain tank share a common drain pump.
However, each of the platen drain tank and chamber drain tank has its own
isolation valve between the tank and the pump to enable emptying of each
tank independently.

[0059]The chamber 100 is operated to accept a wafer 207 from an exterior
module, e.g., MTM, to which the chamber 100 is connected. The wafer 207
is received by the drive rollers 701 and stabilizer roller 605 at a wafer
handoff position in the upper region of the chamber 100. Prior to opening
the chamber 100 to receive the wafer 207, a verification is made that the
pressure within the chamber 100 is sufficiently close to the pressure
within the external module to which the chamber 100 internal volume will
be exposed when the chamber 100 is opened to receive the wafer 207. In
one embodiment, a sufficiently close pressure within the chamber 100 is
within ±10 Torr of the external module pressure. Also, prior to
opening the chamber 100 to receive the wafer 207, a verification is made
that the oxygen content within the chamber 100 is sufficiently close to
the oxygen content within the external module to which the chamber 100
internal volume will be exposed when the chamber 100 is opened to receive
the wafer 207. In one embodiment, a sufficiently close oxygen content
within the chamber 100 is within ±5 ppm of the external module oxygen
content.

[0060]Following receipt of the wafer 207 within the chamber 100, the wafer
207 is moved to the fluid bowl 211 in the lower region of the chamber 100
for the electroless plating process. The platen 209 is heated to a user
specified temperature, and the wafer 207 is held on the platen 209 for a
user specified duration to allow the wafer 207 to heat up. Then, the
platen 209 is lowered to engage the fluid bowl seal 909, so as to cause
an electroless plating solution that is flowing into the fluid bowl 211
to fill the space between the fluid bowl 211 and the platen 209 (above
the fluid bowl seal 909) and to well up and over the periphery of the
wafer 207. The electroless plating solution rises up and over the
peripheral edge of the wafer in a substantially uniform manner so as to
flow from the periphery of the wafer 207 toward the center of the wafer
207 in a substantially concentric manner.

[0061]Following a user defined time period for electroless plating
reaction, the wafer 207 is subjected to a rinsing process. The rinsing
process is performed in the lower region of the chamber 100 by way of the
rinse nozzles 903 and blow down nozzles 905. To initiate the rinsing
process, the platen 209 is raised to a rinse position so as to break its
seal with the fluid bowl seal 909, thus allowing the fluid over the wafer
to drain into the fluid bowl 211.

[0062]Following the wafer rinsing process, the wafer 207 is moved by way
of the platen 209 to the wafer drying position, which is the same as the
wafer handoff position. During the drying process, the wafer is held by
the driver rollers 701 and stabilizer roller 605. The upper and lower
prox heads 203/205 are used to perform the wafer drying process.

[0063]In one embodiment, flow to the upper and lower prox heads 203/205 is
initiated with the prox heads at the prox head docking station 201. In
another embodiment, the upper and lower prox heads 203/205 are moved to
the center of the wafer 207 prior to initiating flow to the prox heads.
If the flow is initiated at the prox head docking station 201, the upper
and lower prox heads 203/205 are moved to the wafer center as the wafer
is rotated. If the flow is initiated at the wafer center, the upper and
lower prox heads 203/205 are moved to the wafer docking station 201 as
the wafer is rotated. Wafer rotation during the drying process is
initiated at an initial rotation speed and adjusted as the prox heads
203/205 are scanned across the wafer. In one embodiment, during the
drying process, the wafer will be rotated a rate extending from about
0.25 revolution per minute (rpm) to about 10 rpm. The wafer rotation
speed will vary as a function of the prox head 203/205 radial position
over the wafer. Also, a scanning speed of the upper and lower prox heads
203/205 is initiated at an initial scan speed and adjusted as the prox
heads 203/205 are scanned across the wafer. In one embodiment, the prox
heads 203/205 are scanned across the wafer at a rate extending from about
1 mm/sec to about 75 mm/sec. At the conclusion of the drying process, the
upper and lower prox heads 203/205 are moved to the prox head docking
station 201.

[0064]During the drying process, the upper and lower prox heads 203/205
are positioned in close proximity to a top surface and a bottom surface
207B of the wafer 207, respectively. Once in this position, the prox
heads 203/205 may utilize IPA and DIW source inlets and a vacuum source
outlet to generate wafer processing meniscuses in contact with the wafer
207 which are capable of applying and removing fluids from the top and
bottom surfaces of the wafer 207.

[0065]The portion of the DIW that is in the region between the prox heads
203/205 and the wafer 207 forms a dynamic liquid meniscus. It should be
appreciated that as used herein, the term "output" can refer to the
removal of fluid from a region between the wafer 207 and a particular
prox head 203/205, and the term "input" can be the introduction of fluid
to the region between the wafer 207 and the particular prox head 203/205.

[0066]FIG. 10 is an illustration showing an exemplary process that may be
conducted by a prox head 203/205, in accordance with one embodiment of
the present invention. Although FIG. 10 shows a top surface 207A of the
wafer 207 being processed, it should be appreciated that the process may
be accomplished in substantially the same way for a bottom surface 207B
of the wafer 207. While FIG. 10 illustrates a substrate drying process,
many other fabrication processes (e.g., etching, rinsing, cleaning, etc.)
may also be applied to the wafer surface in a similar manner. In one
embodiment, a source inlet 1107 may be utilized to apply isopropyl
alcohol (IPA) vapor toward the top surface 207A of the wafer 207, and a
source inlet 1111 may be utilized to apply deionized water (DIW) toward
the top surface 207A. In addition, a source outlet 1109 may be utilized
to apply vacuum to a region in close proximity to the surface 207A to
remove fluid or vapor that may located on or near the surface 207A.

[0067]It should be appreciated that although IPA is utilized in the
exemplary embodiment, any other suitable type of vapor may be utilized
such as any suitable alcohol vapor, organic compounds, hexanol, ethyl
glycol, etc. that may be miscible with water. Alternatives to IPA include
but are not limited to the following: diacetone, diaceton alcohol,
1-methoxy-2-propanol, ethylglycol, methyl-pyrrolidon, ethyllactate,
2-butanol. These fluids may also be known as surface tension reducing
fluids. The surface tension reducing fluids act to increase the surface
tension gradient between the two surfaces (i.e., between the prox heads
203/205 and the surface of the wafer 207.

[0068]It should be appreciated that any suitable combination of source
inlets and source outlets may be utilized as long as at least one
combination exists where at least one of the source inlet 1107 is
adjacent to at least one of the source outlet 1109 which is in turn
adjacent to at least one of the source inlet 1111. The IPA may be in any
suitable form such as, for example, EPA vapor where IPA in vapor form is
inputted through use of a nitrogen carrier gas. Moreover, although DIW is
utilized herein, any other suitable fluid may be utilized that may enable
or enhance the substrate processing such as, for example, water purified
in other ways, cleaning fluids, and other processing fluids and
chemistries. In one embodiment, an IPA inflow 1105 is provided through
the source inlet 1107, a vacuum 1113 is applied through the source outlet
1109, and DIW inflow 1115 is provided through the source inlet 1111. If a
fluid film resides on the wafer 207, a first fluid pressure may be
applied to the substrate surface by the EPA inflow 1105, a second fluid
pressure may be applied to the substrate surface by the DIW inflow 1115,
and a third fluid pressure may be applied by the vacuum 1113 to remove
the DIW, IPA, and the fluid film on the substrate surface.

[0069]It should be appreciated that by controlling the fluid flow amount
onto the wafer surface 207A and by controlling the vacuum applied, the
meniscus 1011A may be managed and controlled in any suitable manner. For
example, in one embodiment, by increasing the DIW flow 1115 and/or
decreasing the vacuum 1113, the outflow through the source outlet 1109
may be nearly all DIW and the fluids being removed from the wafer surface
207A. In another embodiment, by decreasing the DIW flow 1115 and/or
increasing the vacuum 1113, the outflow through the source outlet 1109
may be substantially a combination of DIW and IPA as well as fluids being
removed from the wafer surface 207A.

[0070]Following the wafer drying process, the wafer 207 can be returned to
the external module, e.g., MTM. In one embodiment, prior to opening the
chamber 100 for return of the wafer 207, a verification is made that the
pressure within the chamber 100 is sufficiently close to the pressure
within the external module to which the chamber 100 internal volume will
be exposed when the chamber 100 is opened to receive the wafer 207. In
one embodiment, a sufficiently close pressure within the chamber 100 is
within ±10 Torr of the external module pressure. Also, prior to
opening the chamber 100 for return of the wafer 207, a verification is
made that the oxygen content within the chamber 100 is sufficiently close
to the oxygen content within the external module to which the chamber 100
internal volume will be exposed when the chamber 100 is opened to receive
the wafer 207. In one embodiment, a sufficiently close oxygen content
within the chamber 100 is within ±5 ppm of the external module oxygen
content.

[0071]FIG. 11 is an illustration showing a cluster architecture 1200, in
accordance with one embodiment of the present invention. The cluster
architecture 1200 includes a controlled ambient transfer module 1201,
i.e., a managed transfer module (MTM) 1201. The MTM 1201 is connected to
a load lock 1205 by way of a slot valve 1209E. The MTM 1201 includes a
robotic wafer handling device 1203, i.e., end effector 1203, that is
capable of retrieving a wafer from the load lock 1205. The MTM 1201 is
also connected with a number of process modules 1207A, 1207B, 1207C, and
1207D through respective slot valves 1209A, 1209B, 1209C, and 1209D. In
one embodiment, the processing modules 1207A-1207D are controlled ambient
wet processing modules. The controlled ambient wet processing modules
1207A-1207D are configured to process a surface of a wafer in a
controlled inert ambient environment. The controlled inert ambient
environment of the MTM 1203 is managed such that an inert gas is pumped
into the MTM 1203, and oxygen is purged out of the MTM 1203. In one
embodiment, the electroless plating chamber 100 can be connected to the
MTM 1203 as a processing module. For example, FIG. 11 shows that
processing module 1207A is actually the dry-in/dry-out electroless
plating chamber 100.

[0072]By removing all or most of the oxygen from the MTM 1203 and
replacing it with an inert gas, the MTM 1203 will provide a transition
environment which does not expose a just-processed wafer before or after
an electroless plating process is performed thereon in the chamber 100.
In specific embodiments, the other processing modules 1207B-1207D may be
electroplating modules, electroless plating modules, dry-in/dry-out wet
process modules, or other types of modules that will enable the
application, formation, removal, or deposition of a layer on top of a
wafer surface or feature, or other types of wafer processing.

[0073]In one embodiment, monitoring and control of the chamber 100 and
interfacing equipment, e.g., FHS, is provided through a graphical user
interface (GUI) operating on a computer system that is remotely located
with respect to the processing environment. Various sensors within the
chamber 100 and interfacing equipment are connected to provide a read out
in the GUI. Each electronically actuated control within the chamber 100
and interfacing equipment can be actuated through the GUI. The GUI is
also defined to display warnings and alarms based on various sensor
readings within the chamber 100 and interfacing equipment. The GUI is
further defined to indicate a process state and system conditions.

[0074]The chamber 100 of the present invention incorporates a number of
advantageous features. For example, the implementation of upper and lower
prox heads 203/205 within the chamber 100 provides the chamber 100 with a
dry-in/dry-out wafer electroless plating process capability. The
dry-in/dry-out capability enables the chamber 100 to interface with the
MTM, enables tighter control of chemical reactions on the wafer surface,
and prevents the carrying of chemicals outside of the chamber 100.

[0075]The double walled configuration of the chamber 100 also provides
advantages. For example, the outer structural wall provides for strength
and interface precision, while the inner liner provides a chemical
boundary to keep chemicals from reaching the outer structural wall.
Because the outer structure wall is responsible for providing the vacuum
boundary, the inner liner does not have to be capable of providing a
vacuum boundary, thus enabling the inner wall to be fabricated from inert
materials such as plastic. Additionally, the inner wall is removable to
facilitate chamber 100 cleaning or re-equipping. Also, the strength of
the outer wall enables a decrease in time required to achieve an inert
ambient condition within the chamber 100.

[0076]The chamber 100 provides for control of ambient conditions within
the chamber 100. Use of an inert ambient condition during drying enables
creation of a surface tension gradient (STG) which in turn enables the
prox head processes. For example, a carbon dioxide ambient condition can
be established within the chamber 100 to assist with creation of STG
during the prox head drying process. The integration of STG drying, i.e.,
prox head drying, within a wet process chamber, i.e., within an
electroless plating chamber, enables a multi-stage process capability.
For example, the multi-stage process may include a pre-clean operation by
way of the prox heads in the upper region of the chamber, an electroless
plating process in the lower region of the chamber, and post-clean and
drying operations by way of the prox heads in the upper region of the
chamber.

[0077]Furthermore, the chamber 100 is configured to minimize an amount of
required electroless plating solution, thereby enabling use of
single-shot chemistry, i.e., single use and discard chemistry. Also, a
point of use mixing approach is implemented to control electrolyte
activation before deposition on wafer. This is accomplished by use of the
mixing manifold which incorporates an injector tube, where the activating
chemistry is injected into a flow stream of chemicals surrounding the
injector tube, as close as possible to the fluid bowl dispense locations.
This increases reactant stability, and reduces defects. Additionally, the
quenching rinse capability of the chamber 100 provides for greater
control over electroless plating reaction time on the wafer. The chamber
100 is further configured to be easily cleaned by introducing a
"backflush" chemistry into the limited volume of the fluid bowl. The
"backflush" chemistry is formulated to remove metal contaminants that may
be introduced by the electroless plating solution. In other embodiments,
the chamber 100 can be further configured to incorporate various types of
in-situ metrology. Also, in some embodiments, the chamber 100 can include
radiant or absorptive heating sources to initiate electroless plating
reactions on the wafer.

[0078]While this invention has been described in terms of several
embodiments, it will be appreciated that those skilled in the art upon
reading the preceding specifications and studying the drawings will
realize various alterations, additions, permutations and equivalents
thereof. Therefore, it is intended that the present invention includes
all such alterations, additions, permutations, and equivalents as fall
within the true spirit and scope of the invention.